Centaur (rocket Stage) - Development History

Development History

Development started in 1956 at NASA's Lewis Research Center, now the Glenn Research Center, but proceeded slowly, with the first (unsuccessful) test flight in May 1962. In the late 1950s and early 1960s Centaur was proposed as a high energy upper stage for the Saturn I, Saturn IB and Saturn V rockets, under the designation S-V ("Saturn V") in accordance with the numbering of other stages of Saturn rockets. However, the first successful Centaur flight did not take place until 1965. By then, NASA had replaced the Centaur with much larger upper stages for the Saturn.

From 1966 to 1989, the Centaur-D was used as the upper stage for 63 Atlas rocket launches. Fifty-five of these launches were successful.

From 1974 to 1977, the Centaur-D-1T was used as the third stage on seven Titan IIIE launches, six of which were successful.(Only the first launch, used to test the overall launch vehicle design rather than to launch a space vehicle, was classed as a failure; it did however, prove out the design.) Spacecraft launched by these vehicles included Viking 1, Viking 2, Voyager 1, Voyager 2, Helios 1 and Helios 2.

A major change to the Centaur was made in the early 1980s. A hydrazine monopropellant attitude control system replaced the previous hydrogen peroxide system. The hydrogen peroxide powered boost pumps were deleted and the RL-10 engines fed directly via tank pressure — a significant reduction in system complexity.

A new version, the Centaur-G, was developed for use with the Space Shuttle. It was optimized for installation in the Orbiter payload bay by increasing the hydrogen tank diameter to 14 feet while retaining the 10-foot-diameter (3.0 m) oxygen tank. Its initial mission was to be the Galileo scientific probe to Jupiter.

The Centaur, as carried in the Shuttle payload bay, required an extremely complex airborne support system, which was integrated into the Centaur Integrated Support System, the CISS. In addition to controlling Centaur pressurization in flight, the CISS had to be able to dump propellants overboard quickly in the event of a Return To Launch Site Abort, a capability needed to permit the Orbiter to land safely. After the Challenger accident, NASA realized that it was far too risky to fly the Centaur on the Shuttle.

The decision to terminate the Shuttle/Centaur program spurred the United States Air Force to create the Titan IV, which, in its 401A/B versions, used the Centaur-T, also with a 14-foot-diameter (4.3 m) hydrogen tank, as its final stage. This vehicle was capable of launching payloads which had originally been designed for the Shuttle-Centaur combination. In the Titan 401A version, a Centaur-T was launched nine times between 1994 and 1998. In the Titan 401B version, a Centaur-T was launched seven times, with one failure, between 1997 and 2003. The last Titan-Centaur launch was in 2003.

Another major Centaur reconfiguration was done for the Atlas III vehicle with a change from dual RL-10 engines as standard to a single RL-10. This change was accomplished while retaining the ability to revert to dual engines should mission requirements dictate. For most missions a single RL-10 is optimal (or adequate), hence a substantial reliability and cost benefit was realized.p. 251.

A "Common Centaur" was unveiled by Lockheed Martin Space Systems on November 30, 1999. The stretched Centaur stage was 11.68 m in length, 1.7 m longer than the Centaur used on Atlas IIA and IIAS rockets at that time.